Drive Mechanism for Launcher

ABSTRACT

A projectile launcher has a drive mechanism for rotating a rotary magazine. The drive mechanism including a drive shaft fixed for rotation with the magazine about the axis. The drive shaft has a plurality of grooves. A detent member is in engagement with the drive shaft. Relative axial movement between the detent member and the drive shaft causes rotation of the drive shaft and thus the magazine, about the axis, without movement of the drive shaft an axial direction.

BACKGROUND OF THE INVENTION

This invention relates to a launcher of the type used to launch less lethal projectiles such as tear gas and markers. Some launchers of this type have a rotary magazine that holds several projectiles. This invention relates to a drive mechanism for rotating the magazine between shots to bring the next projectile into firing position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, partially cut away, of a launcher that is a first embodiment of the invention, including a drive mechanism in accordance with the present invention;

FIG. 2 is a sectional view through a portion of the drive mechanism of the launcher of FIG. 1, taken generally along line 2-2 of FIG. 1;

FIG. 3 is an elevational view of a portion of a drive shaft, showing sets of grooves on the exterior surface of the drive shaft;

FIG. 4 is another elevational view of the portion of a drive shaft, rotated about its axis, and showing schematically a detent in several different operational positions with respect to the drive shaft; and

FIG. 5 is an illustration of a portion of a drive shaft that is part of a drive mechanism that is a second embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 is a pictorial illustration of a launcher 10 including a drive mechanism 12 that is a first embodiment of the invention. The general configuration and structure of the launcher 10, other than the drive mechanism 12 of the invention, is known. The launcher 10 includes a stock 20, a grip 22, a trigger 24, and a frame 26 that supports those parts. Together, those parts form what is herein referred to, for convenience, as a “base” 28 of the launcher 10. The launcher 10 also includes a magazine 30 and a barrel 34.

The magazine 30 is supported on the base 28 for rotation relative to the base about an axis 32. The magazine 30 has a plurality of chambers 33. The number of chambers 33 may vary, depending on the particular launcher 10. In the illustrated embodiment, the magazine has four chambers 33. Each chamber 33 is adapted to receive a cartridge (not shown) that includes a projectile. The magazine 30 is rotatable about the axis 32 to and through a number of index positions.

The barrel 34 is supported on the base 28 and projects forward (to the left as viewed in FIG. 1) from the base and the magazine 30. The barrel 34 is aligned with the uppermost chamber 33 in the magazine 30 when the magazine is in one of its index positions. The launcher 10 includes a known firing mechanism for actuating the particular cartridge that is in the uppermost chamber 33, when the trigger 24 is pulled, to cause the projectile that is part of that cartridge to be propelled from the barrel 34.

The drive mechanism 12 is operable as described below to rotate the magazine 30 to and through its several index positions. The drive mechanism 12 includes as its two main components a drive shaft 40 and a detent or détente member 60.

The drive shaft 40, decribed below in more detail, is an elongate, generally cylindrical element that is supported on the body for rotation about the axis 32. The drive shaft 40 projects forward under the barrel 34. The rearward or inner end portion of the drive shaft 40 is fixed for rotation with the magazine 30.

Two support shafts 62 extend parallel to the barrel 34, on opposite sides of the drive shaft 40. The support shafts 62 are fixed to the frame of the launcher 10. The support shafts 62 support a saddle 66 for sliding movement along the support shafts 62, in a direction parallel to the axis 32. The saddle 66 encircles and helps to support the drive shaft 40. The saddle 66 is slidable axially along the support shafts 62 and the drive shaft 40.

The saddle 66 carries the detent 60 in a manner and location so that the detent engages the drive shaft 40. A spring or other biasing member 67 is located between the saddle 66 and the detent 60, and biases the detent into engagement with the derive shaft 40. As described below, when the saddle 66 is moved (slid back and forth) along the length of the drive shaft 40, the engagement of the detent 60 with the drive shaft 40 causes the drive shaft to rotate about the axis 32, thus rotating (indexing) the magazine 30 as desired.

The drive shaft 40 has a grooved portion 42 that extends for a portion of the length of the drive shaft 40 and that is engaged by the detent. The grooved portion 42 has a number of groove sets 44 on its outer surface. The number of groove sets 44 is equal to the number of chambers 33 in the magazine 30. Thus, in the illustrated embodiment, the drive shaft 40 has four groove sets 44.

Each groove set 44 includes a rotating groove 46 and a return groove 48. The rotating groove 46 is helical in configuration, that is, it extends for the length of the grooved portion 42 but wraps partially (in this case, ninety degrees) around the circumference of the drive shaft 40. The return groove 48 is straight, that is, it extends along the length of the grooved portion 42 of the drive shaft 40, without wrapping around the circumference of the drive shaft.

The rotating grooves 46 and the return grooves 48 intersect each other at their forward ends, and also intersect each other at their back ends (closer to the magazine 30). Specifically, at each forward intersection, the depth of the grooves 46 and 48 increases, to form a front indent 50 in the surface of the drive shaft 40 that is deeper than the depth of the grooves. Similarly, at each back intersection, the depth of the grooves 46 and 48 increases, to form a back indent 52 in the surface of the drive shaft 40 that is deeper than the depth of the grooves.

FIG. 4 illustrates schematically illustrates the engagement of the detent 60 and the drive shaft 40 during operation of the drive mechanism 12. When the detent is in the position indicated by the circle 61, the drive mechanism 12 is in what is referred to herein as a “start” position. The saddle 66 is all the way forward along the drive shaft 40 and the support shafts 62. The detent 60 is located in one of the front indents 50, at the forward end of both a rotating groove 46 and a return groove 48. The engagement of the detent 60 in the front indent 50 is sufficient to hold the parts of the drive mechanism 12 in this position, with one of the chambers 33 of the magazine 30 thus being held in an index position.

When the saddle 66 is moved (pulled) back toward the magazine 30, the detent 60 is forced out of the front indent 50, moving radially outward against the bias of the spring 67, and into the rotating groove 46 as indicated by the circle 63. The edge of the return groove 48 at the forward indent, and the edge of the rotating groove 46 at the forward indent, are configured to ensure that the detent 60 moves rearward into the rotating groove 46 and not into the return groove 48.

As the saddle 66 continues to move rearward, it moves in a direction parallel to the axis 32. Because the saddle 66 and the detent 60 are blocked from rotation by the support shafts 62, the engagement of the detent 60 with the helical rotating groove 46 causes the detent 60 to exert a rotational force on the drive shaft 40, rotating the drive shaft 40 as the saddle moves back. As the drive shaft 40 rotates, so also does the magazine 30, which is fixed for rotation with the drive shaft 40.

When the saddle 66 reaches its full rearward position, the force of the spring 67 causes the detent 60 to move radially inward into the back indent 52 at the back end of the rotating groove 46, as indicated by the circle 64. The drive shaft 40 ceases rotation. The magazine 30 also ceases rotation. The magazine 30 is at its next index position.

The saddle 66 is then moved (pushed) forward, out of the back indent 52, in a direction away from the magazine 30. The detent 60 is forced out of the back indent 52, radially outward against the bias of spring 67, into the return groove 48 as indicated by the circle 65. The edge of the return groove 48 at the back indent 52, and the edge of the rotating groove 46 at the back intent, are configured to ensure that the detent 60 moves into the return groove and cannot back track into the rotating groove.

As the saddle 66 continues to move forward, because the return groove 48 extends parallel to the axis 32, no rotational force is exerted on the drive shaft 40. Therefore, the magazine 30 does not rotate out of its previously attained index position. When the saddle 66 reaches its full forward position, the force of the spring 67 causes the detent 60 to move into the front indent 50 at the front end of the return groove 48 (which is also front end of the next rotating groove 46). Thus, the cycle is complete and the drive mechanism 12 is again in the start position, ready to rotate the magazine 30 again.

Action of the drive mechanism 12 can be reversed if desired. That is, the groove sets 44 can be positioned and oriented on the drive shaft 40 so that a forward movement of the saddle 66 causes rotation of the drive shaft, with the detent 60 traveling along a rotating groove 46, in which case a rearward movement of the saddle would result in the detent traveling along a return groove 48. This configuration might be desired in some cases to deal with the effects of launcher recoil, or for other reasons.

In a second embodiment, the drive shaft has two grooved portions, back to back. This embodiment is illustrated in FIG. 5. Specifically, a drive shaft 40 a has two grooved portions 42 a and 42 b. The grooved portions 42 a and 42 b are oriented the same as each other. The grooved portions 42 a and 42 b are engaged by two detents (not shown) on a saddle that may be longer to accommodate the spacing of the two detents, which may be in the range of, for example, three to four inches. The use of two detents and two grooved portions means that rotational (driving) force is spread over a larger surface area, thus reducing the possibility of skipping or other detrimental effects.

From the foregoing description of the invention, those skilled in the art will perceive improvements, changes and modifications. For example, alternative electrical circuitry can be used so long as it provides the same result. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims. 

1. A projectile launcher including: a base; a barrel supported on the base; a magazine supported on the base for rotation relative to the base and the barrel about an axis, the magazine having a plurality of chambers adapted to contain a plurality of projectiles to be launched individually through the barrel; and a drive mechanism for selectively rotating the magazine relative to the base between a plurality of index positions, in each index position one of the chambers being aligned with the barrel for launching the projectile in the one chamber through the barrel; the drive mechanism including a drive shaft fixed for rotation with the magazine about the axis, the drive shaft having a plurality of grooves; the drive mechanism also including a detent in engagement with the drive shaft, the detent being manually movable in a direction parallel to the axis and relative to the drive shaft to rotate the drive shaft and thereby the magazine about the axis.
 2. A launcher as set forth in claim 1 wherein the plurality of grooves includes a plurality of groove sets, each groove set including a rotating groove and a return groove, the number of groove sets on the drive shaft being equal to the number of chambers in the magazine.
 3. A launcher as set forth in claim 3 wherein each rotating groove is helical and each return groove straight.
 4. A launcher as set forth including a manually engageable saddle that is supported for axial sliding movement relative to the drive shaft, the saddle carrying the detent, manual sliding movement of the saddle causing indexing movement of the magazine.
 5. A launcher as set forth in claim 3 wherein at each intersection between a rotating groove and a return groove there is formed an indent for holding the detent and thus resisting relative movement between the detent and the drive shaft and thereby resisting rotation of the magazine.
 6. A drive mechanism for a projectile launcher including a magazine rotatable about an axis between a plurality of index positions, the drive mechanism comprising a drive shaft fixed for rotation with the magazine about the axis, the drive shaft having a plurality of grooves, and a detent member in engagement with the drive shaft, relative axial movement between the detent member and the drive shaft producing rotation of the drive shaft about the axis.
 7. The drive mechanism of claim 6 wherein half of the plurality of grooves are rotating grooves and the other half of the grooves are return grooves.
 8. The drive mechanism of claim 7 wherein the rotating grooves are helical and the return grooves are straight, each rotating groove intersects at its ends with a return groove, and each return groove intersects at its ends with a rotating groove. 